Timer device



July 14, 1970 s. MYERS 3,520,124

TIMER DEVICE Filed Feb. 13, 1969 Fifii (26 INVENTOR SUMNER MYERS 5| W j g ATTORNEYS United States Patent Ofice 3,520,124 Patented July 14, 1970 3,520,124 TIMER DEVICE Sumner Myers, 3248 Patterson St. NW., Washington, D.C. 20015 Filed Feb. 13, 1969, Ser. No. 799,055 Int. Cl. G01d 21/00; G04f 1/00 US. Cl. 58-1 11 Claims ABSTRACT OF THE DISCLOSURE A device for indicating a predetermined time interval based on two or more materials which react, either chemically or physically over a predetermined period to produce a termination signal. The reacting materials are carried on a base member and are separated by a barrier preventing contact therebetween. Upon elimination of the barrier, a commencement signal is produced indicating the time reaction is underway. In preferred embodiments the commencement and termination signals involve abrupt color changes. The device finds particular utility as an elapsed time indicator for indicating motor vehicle parking time.

This invention relates to timing devices for measuring a predetermined time interval. More specifically, it relates to a self cancelling time ticket or device based on a reaction system of two or more components. The device is preferably in the form of a ticket or the like which provides a signal that the reaction is underway (a commencement signal) and a termination signal indicating that the reaction is complete and that the predetermined time period has elapsed. The commencement signal and termination signal may be in the form of color changes, although other signals are within the scope of the invention.

It is among the objects of this invention to provide a simple, inexpensive, fool-proof timing device for indicating a predetermined time period. Other objects and advantages will be apparent from the description herein.

The device has utility in indicating elapsed time in a wide variety of applications. An important application is in indicating motor vehicle parking periods. For example, a motorist would purchase or otherwise be provided with time tickets containing a reaction system having a two hour reaction time. Upon parking the vehicle in a two hour parking zone, the motorist would activate the reaction system on the ticket and aflix the ticket to the windshield of his vehicle. Upon activating the system, the commencement signal is produced, indicating that the reaction is underway. After two hours the reaction is complete and an abrupt termination signal is produced. Thus, law enforcement ofiicials can readily detect vehicles which have been parked longer than the parking limit. The device thus serves the same function as a parking meter but at much less cost, particularly the initial investment, meter maintenance, and collection costs. Other applications include elapsed time indicators for indicating expiration times on drugs, chemical, photographic film and the like.

The term reaction system as used in the specification and claims includes both chemical reactions and purely physical reactions. Examples of chemical reactions which may be employed are so-called clock reactions such as the iodine clock reaction, the formaldehyde clock reaction, the methylene blue-sugar reaction or reactions indicating pH change. Example of physical reactions include the disintegration by a solvent of time capsules which may contain a dye, for example, or which contain a material chemically reactive with the solvent to produce a termination signal.

The reacting components forming the reaction system are physically separated by barrier means. To activate the system, the barrier is eliminated or broken, and the commencement signal is produced indicating the reaction is underway.

Referring to the drawing:

FIG. 1 is a partial view of a motor vehicle having the timer device displayed on the windshield of the vehicle.

FIGS. 28 illustrate various forms of the invention, to be described in detail herein.

In FIG. 1, a motor vehicle 20 is shown having a time ticket 21 displayed on the windshield 21.

In FIG. 2, a transparent base 23 of plastic film or cellophane or the like is coated in separate areas with a reactant 24 and a second reactant 25. A strippable cover sheet 26 covers both reactants. To activate the device, the cover sheet 26 is removed and the coated base 23 folded at 27 to place the reactants in contact. FIG. 2A illustrates the device after the reacion has commenced. In practice the cover sheet could be opaque and colored green, for example. The reactants 24 and 25 are coated on the base in the form of clear or white gels. Thus upon activating the device as shown in FIG. 2A the ticket now appears clear or white, the commencement signal. After the reaction is complete the device abruptly turns red, for example, the termination signal, indicating the predetermined time period has elapsed.

The following examples illustrate reaction systems utilizable in the embodiment shown in FIGS. 2 and 2A:

EXAMPLE I Reactant 24 comprised potassium iodate contained in aqueous gelatin gel.

Reactant 25 comprised the following in aqueous gelatin gel: starch, sodium sulfite, salicylic acid, and sulfuric acid.

The above system is the iodine clock reaction. The reactant coatings are translucent white. After the reaction is complete, the device abruptly turns blue. By suitable manipulation of concentration of the reactants, elapsed times of from 30 minutes to two hours can be measured.

EXAMPLE II Reactant 24 comprised 0.1 N HCl and 1% phenolphlthalein in ethyl alcohol in aqueous gelatin gel, a clear ge Reactant 25 comprised finely powdered trisodium phosphate microencapsulated in polyvinyl alcohol, forming a white coating.

When the aqueous medium disintegrates the polyvinyl alcohol coating on the phosphate particles, the material turns red. By way varying the thickness of of the polyvinyl alcohol coating, elapsed times of from one to eight hours can be measured.

EXAMPLE III Reactant 24 comprised 0.1 N HCl in aqueous gelatin gel.

Reactant 25 comprised finely divided ultramarine blue microencapsulated in polyvinyl alcohol, forming a white coating. By varying the thickness of the polyvinyl alcohol coating, elapsed times of from one to eight hours can be measured. The system turns deep blue upon completion.

FIG. 3 illustrates another embodiment of the invention. A transparent plastic envelope 28 is provided with a frangible barrier 29 separating compartments 30 and 31. An alkali soluble barrier 32 separating compartments 31 and 33. Compartment 30 contains 0.1 N NaOH which is colorless. Compartment 31 contains water containing a drop of 1% phenolphthalein in ethanol. Barrier 29 is ruptured by squeezing compartment 30 and the resulting solution turns red, the commencement signal. Barrier 32 is formed of maleic anhydride methyl vinyl ether copolymer which is alkali soluble. Compartment 33 contains a drop of 2% methyl green in ethanol. When barrier 32 is disintegrated by the alkali, the solution escapes into compartment 33 and turns violet. By varying the thickness of barrier 32, predetermined times of 30 minutes to 4 hours can be measured.

FIG. 4 illustrates a further embodiment. A transparent envelope 34 is provided with a frangible barrier 35 separating compartments 36 and 37. Compartment 36 contains 0.1 N HCl. Compartment 37 contains a single crystal of methyl orange plus the microencapsulated ultramarine blue of Example III. The barrier 35 is ruptured by bending the device as shown, whereupon the solution turns red. After the polyvinyl alcohol coating has disintegrated, the solution is blue.

FIG. shows another embodiment. Envelope 38 has a frangible barrier 39 and is sealed to absorbent filter paper 40. The absorbent paper 40 is impregnated with aqueous potassium iodate plus 0.01% methyl yellow and is dried. The paper is yellow. Envelope 38 contains the remaining iodine clock reagents, as set forth in Example I, in aqueous solution, Envelope 38 is squeezed, rupturing the barrier 39 and saturating paper 40, which now turns red. Upon completion of the reaction, the paper turns blue.

FIG. 6 illustrates a further embodiment. Transparent envelope 41 is provided with a frangible barrier 42 forming compartment 43 which contains 0.1 N acetic acid and litmus extract, producing a red color. Compartment 44 is filled with a microporous material 45 such as polyurethane foam, for example, compartment 46 contains cotton or the like impregnated with 0.1 N sodium hydroxide and subsequently dried. Upon breaking the barrier 42, the acetic acid and litmus solution move by capillary action through the microporous material progressively turning it red. When the solution migrates to the compartment 46 the caustic impregnated absorbent material turns blue, indicating the termination. By proper selection of pore size of the microporous material, elapsed times of from minutes to one hour can be measured.

A further embodiment is illustrated in FIG. 7. Transparent envelope 47 is provided with a frangible barrier 48 forming compartments 49 and 50. Compartment 49 contains a solution of one reactant. Compartment 50 is filled with the second reactant microencapsulated in a slowly soluble material and an indicator. Examples of suitable reactants are those described in connection with FIG. 4. The reaction is commenced by squeezing compartment 49, thereby fracturing barrier 48.

Another embodiment is shown in FIG. 8. A base member 51 is coated with frangible microcapsules 52 containing one reactant. A second coating of frangible microcapsules 53 containing a second reactant and a dye is superposed on the first coating. The reaction is initiated by fracturing the microcapsules, as by rubbing with a coin 54. Microcapsules 52 and 53 are, for example, white before being fractured. Upon fracture, the dye and the reactants are released, signalling the commencement of the reaction. The reactants may be the iodine clock reactants of Example I, the encapsulated potassium iodate containing, for example, a yellow dye.

It will be apparent to those skilled in the art that many other chemical or physical reaction systems may be employed in the present invention. By suitably controlling the concentrations of the reactants, in the case of chemical reaction systems, or by control of soluble barrier thickness, reaction times varying from a few minutes to several days may be obtained.

I claim:

1. A device for indicating a predetermined time interval comprising a base carrying two materials which upon contact comprise a reaction system requiring a predetermined time interval from commencement to termination, said reaction system producing a termination signal upon termination, barrier means preventing contact of said two materials and means for producing a signal coincident with elimination of said barrier means for signaling commencement of the reaction.

2. The device set forth in claim 1 wherein said commencement and termination signals involve abrupt color changes.

3. The device set forth in claim 1 wherein said reaction system comprises a chemical reaction having a predetermined induction period whereby an abrupt termination signal is produced.

4. The device set forth in claim 3 wherein said reaction is the iodine clock reaction.

5. The device set forth in claim 1 wherein one of said reaction materials comprises a solvent which attacks and disintegrates a coating covering the second reactant.

6. The device set forth in claim 1 wherein said reactant materials are separately encapsulated in frangible microcapsules coated on said base.

7. The device set fort-h in claim 6 wherein the separately encapsulated reactant materials comprise the reactants for the iodine clock reaction, one of said encapsulated reactants including a dye for signaling commencement of the reaction.

8. The device set forth in claim 1 wherein the reactant materials produce a pH change and contain an indicator responsive to said pH change to produce the commencement signal.

9. The device set forth in claim 1 wherein the reactant materials produce a pH change and contain an indicator responsive to said pH change to produce the termination signal.

10. The device set forth in claim 1 wherein said reactant materials are coated on separate areas of said base and said barrier means is a strippable sheet covering said coated base whereby the reaction is commenced by contacting said separately coated areas together.

11. The device set forth in claim 1 wherein said barrier means comprises a frangible wall separating the reactant materials.

References Cited UNITED STATES PATENTS 2,337,534 12/1943 Barber 581 2,671,424 3/1954 Herring et a1 116-114 X 3,018,611 1/1962 BiritZ 58-1 3,420,635 1/1969 Davis 1l6-1 14 X FOREIGN PATENTS 2,432 1/1910 Great Britain.

RICHARD B. WILKINSON, Primary Examiner S. A. WAL, Assistant Examiner US. Cl. X.R. 23253; 116-114 

